The present invention generally relates to finding of a power source failure that occurs in a storage system.
The technology disclosed in, for example, Japanese Published Unexamined Patent Application No. 2006-126972 is known as the technology related to finding of a power source failure in a storage system. According to the technology described in Japanese Published Unexamined Patent Application No. 2006-126972, the power source monitoring portion of the HDD (hard disk drive) detects the occurrence of a failure in the power source of the HDD, and the power source monitoring portion informs a control portion within the storage system of the failure.
As the configuration of the storage system, for example, there is sometimes adopted a configuration in which one or more units equipped with a plurality of media drives (referred to as “expansion enclosures” hereinafter for convenience) are connected in series to a unit having a controller (referred to as “base enclosure” hereinafter for convenience) via components such as cables or backboards. In other words, there is adopted a configuration in which a base enclosure and one or more expansion enclosures are connected in multi-stages. According to this type of configuration, the storage capacity of the storage system can be changed by changing the number of expansion enclosures.
As this type of storage system, there is, for example, a storage system having a configuration shown in FIG. 1.
For example, n number of expansion enclosures 3-1 through 3-n (n is an integer of 1 or more (in the illustrated example, n is an integer of 2 or more)) are connected to a base enclosure 10.
The base enclosure 10 has duplex controllers (abbreviated as “CTL” hereinafter) 1A and 1B. The CTLs 1A and 1B have drive I/F control circuits 2A and 2B respectively. The drive I/F control circuit 2A controls drive I/F circuits 6A-1 through 6A-n and the drive I/F control circuit 2B controls drive I/F circuits 6B-1 through 6B-n. For example, the drive I/F control circuits 2A and 2B control a drive I/F circuit (6A-1, for example) to which a target media drive (8-1-0, for example) is connected, and thereby access this media drive.
The expansion enclosure 3-n has duplex AC/DC power sources (simply referred to as “power sources” hereinafter) 4A-n and 4B-n, duplex drive control boards 5A-n and 5B-n, and m+1 number of media drives 8-n-0 through 8-n-m (m is an integer of 0 or more (in the illustrated example, m is an integer of 1 or more)). The drive control boards 5A-n and 5B-n have, respectively, the drive I/F circuits 6A-n and 6B-n, which are interface circuits for the media drives 8-n-0 through 8-n-m. The media drives 8-n-0 through 8-n-m are connected to each of the drive I/F circuits 6A-n and 6B-n. The power sources 4A-n and 4B-n convert AC power supplied from AC power sources (commercial power sources) 7A-n and 7B-n respectively into DC power and then supply the DC power to the drive I/F circuits 6A-n and 6B-n, and media drives 8-n-0 through 8-n-m.
The drive I/F control circuit 2A (and 2B) of the base enclosure 10 is connected in series to the drive I/F circuits 6A-1 through 6A-n (and 6B-1 through 6B-n) of the respective expansion enclosures 3-1 through 3-n via fiber channel cables 11A-1 through 11A-n (and 11B-1 through 11B-n). Accordingly, a fiber channel signal line 11A (and 11B) is formed (specifically, for example, an FC-AL (Fiber Channel-Arbitrated Loop) having the drive I/F circuits 6A-1 through 6A-n (and 6B-1 through 6B-n) and the fiber channel cables 11A-1 through 11A-n (and 11B-1 through 11B-n) is configured).
In this type of storage system, when a failure occurs in the power sources 4A-1 through 4A-n and 4B-1 through 4B-n of the expansion enclosures 3-1 through 3-n, it is demanded that the failure is detected and a report thereof is output.
The following method can be considered as a method for realizing such detection and output.
Specifically, as shown in FIG. 1, in the expansion enclosures 3-1 through 3-n the drive control boards 5A-1 through 5A-n and 5B-1 through 5B-n are provided respectively with power source abnormality detection circuits 9A-1 through 9A-n and 9B-1 through 9B-n that monitor voltage of power wires 15-1 through 15-n. In the expansion enclosure 3-n, for example, the power source abnormality detection circuits 9A-n and 9B-n are supplied with power from the power sources 4A-n and 4B-n respectively. The power source abnormality detection circuits 9A-1 through 9A-n and 9B-1 and 9B-n are connected respectively to the drive I/F control circuits 2A and 2B via cables 13A-1 through 13A-n and 13B-1 through 13B-n in which signals indicating a power source failure flow (“power source abnormality informing cable” hereinafter). In the expansion enclosure 3-n, for example, when a failure occurs in both the power sources 4A-n and 4B-n, the power source abnormality detection circuits 9A-n and 9B-n detect the abnormality of the power sources 4A-n and 4B-n (decrease of voltage in the power wire 15-n), and transmit the signals indicating the power source abnormality to the drive I/F control circuits 2A and 2B, respectively, via the power source abnormality reporting cables 13A-n and 13B-n. When both the drive I/F control circuits 2A and 2B receive the signals indicating the power source abnormality from the power source abnormality detection circuits 9A-n and 9B-n respectively, the occurrence of power source failures, which are failures of both the power source abnormality detection circuits 9A-n and 9B-n, is found.
However, according to this configuration, the following problems arise.
(1) The power source abnormality reporting cable is required in each drive I/F circuit. For this reason, it is difficult to form wiring within the storage system. Furthermore, the greater the number of levels of the drive I/F circuits, the longer the distance between the controller and the drive I/F circuit at the end, and, since the there are a large number of power source abnormality reporting cables, a high-performance circuit might be required in the controller in order to receive a report on a power source failure.
(2) The power source abnormality detection circuit is required in each drive I/F circuit. Power consumption is high due to the provision of the power source abnormality detection circuits.
(3) As described above, the power source abnormality reporting cable and the power source abnormality detection circuit are required in each drive I/F circuit. For this reason, the number of parts increases as the number of the cables and circuits increases, whereby the number of targets to be maintained (or inspected, for example) is increased.